Mooring of vessels

The design of mooring at berth can be broken down into a certain number of steps by thinking in very basic terms

The problem at hand is – we are given a vessel, and we need to moor it to a berth. The first question which pops is why at all we need to berth the vessel? Why can’t we just leave it floating? Well, if we leave it floating, it is subject to environmental elements of wind, current, waves, tides etc. These will make it drift, with the possibility of hitting another vessel in the vicinity

The next thought that comes is: what’s the best way to secure it to a berth? The simplest solution we can imagine is using ropes to tie it to strong and fixed structures on the berth. A ship needs equipment like bollards, fairleads and winches which can help secure the rope from ship to the mooring equipment on the berth

So, how do we go about selecting the right sized rope? What about the bollards, fairleads and winches on the vessel? How big should they be? It is natural to expect that a bigger ship will require bigger sized equipment (bollard, winches, fairleads etc.) and ropes to secure it. How could we devise a method to do it

In simplest terms, mooring involves tying the vessel to a berth using ropes so that the vessel stays in place and is not carried away by the environment. The environment may comprise wind, current, tides, waves, ice, swell etc. which the berth is subject to.

To know how many and how big ropes and what size equipment are needed, we should have an estimate of how much environmental forces the vessel is subject to. Once we know the forces, we can go about tying ropes in such a way that these are able to resist the forces

Hence, the steps to designing a mooring system can be

Step 1: Get the environmental data for the berth – wind, wave, current, tide etc

Step 2: Calculate, based on the size and geometry of the vessel, the total environmental forces on the vessel

Step 3: Design a mooring system comprising ropes and equipment adequate for resisting the environmental forces obtained in Step 2. This includes designing the mooring pattern and selecting the right equipment